1. Field of the Invention
This invention relates to demand type devices that are operated to fumigate a volatile material, under vacuum, into an intake air flow of a conventional engine to increase fuel burn efficiency and to boost power, and in particular, to devices for fumigation of liquified petroleum gas (LPG) into the engine intake air supply of an inlet of a turbo charged diesel engine.
2. Prior Art
Boost systems that function to fumigate a combustible gaseous or vaporous fuel into an engine, to mix with the engine air, for combustion within the engine cylinders, and provide a power boost have been employed for many years, with such applications, however, have generally been limited to gasoline type engines. Where, like the present invention, systems for the fumigation of liquified petroleum gas (LPG), and in particular propane gas, into, the intake air supply for combustion in a gasoline engine, rather than in a diesel engine like that of the invention. Such earlier systems have maintained the LPG or propane source in a gaseous state and have passed that gas directly into a fuel flow directed into engine cylinder firing chambers. Whereas, the invention provides for maintaining the LPG source in a liquid state and provides for a LPG vaporization with a utilization of engine heat, presenting an active LPG flow into the air supply that thoroughly mixes with the diesel engine fuel flow, to greatly improve the burn efficiency of the engine fuel.
Novel to the invention, the system of the invention operates under a vacuum to provide for an instant flow of vaporized LPG, on demand, and, requires less than one second for line purging after an operator lifts his foot off from the accelerator and manifold pressure drop, turning off the valve as commanded by pressure switches. With, for the invention to operate, the engine must be running and a minimum of point five (0.5) inches of water column vacuum must be present. In operation, when line pressure falls to three and one half (3 xc2xd) psi, the LPG flow will be shut off, cutting off boost.
It is a principal object of the present invention to provide a liquified petroleum gas (LPG) into an assist convertor and regulator in a fumigation process operated under vacuum, supplying vaporized LPG into an intake air supply of a combustion engine, preferably a diesel engine, for mixing and burning with engine fuel to provide a power boost and a more efficient fuel burning.
Another object of the present invention is to provide a fumigation system that includes a converter cutoff valve that controls flow of a liquified LPG feed into the converter and regulator that, in turn, is passed into the intake air supplied to the engine, that is operated under vacuum of between minimum and maximum pressures, providing for opening, at a lesser vacuum, and with closure taking place at a greater vacuum.
Another object of the present invention is to provide an LPG fumigation system as an assist converter and regulator that will afford a vehicle operator with a rapid response when boost is initiated and will immediately shut off when the operator relaxes pressure on the engine throttle.
Another object of the present invention is to provide an LPG fumigation system as an assist converter and regulator system having a housing that is ported to pass coolant from the engine cooling system for heating an LPG passage therethrough to vaporize the LPG and fed it, on demand, into the engine intake air supply, providing a power boost when burned with the engine fuel.
Still another object of the present invention is to provide an inlet valve for an LPG fumigations assist converter and regulator that includes a valve body and seat arrangement where the respective contacting surfaces slope at slightly different angles as an interference fit, to provide positive valve closure.
Still another object of the present invention is to provide a housing for a converter and regulator that is manufactured in sections by machining solid aluminum billets, avoiding porosity in the housing interior as is common with cast housings, and the housing sections are arranged for convenient connection together.
Still another object of the present invention is to provide an LPG fumigation assist converter and regulator housing that is ported internally to pass a hot water flow from the engine cooling system for vaporizing LPG that is drawn through a separate housing, under vacuum, to flow into and mix with an engine inlet air supply of, preferably, an engine turbo charger, with the combined flows to pass into the engine for mixing with fuel for combustion in an engine combustion chamber, providing an efficient fuel burn and power boost.
In accordance with the above objects the present invention is in a liquified petroleum gas (LPG) fumigation system of an assist converter and regulator that includes a housing that is ported to internally pass a hot engine coolant flow, heating the housing interior. A pair of serpentine like passages are formed between LPG inlet and outlet ports that are separated from the engine coolant flow and receive a flow of LPG, in liquid form, on demand, from an LPG tank, with the heat transfer from the housing walls to vaporize the LPG flow. The LPG vapors are pulled by a vacuum into, so as to mix with an engine intake air supply flow, and the mixed air and LPG flows are then directed into an engine intake air inlet. Which engine intake air inlet is preferably an intake air supply inlet to a turbo charger of a diesel engine, with the mixed flows to pass into the engine and mix in the engine combustion chambers with engine fuel, for combustion. In practice, for operating the system, the engine must be running at a high enough RPM to create a slight vacuum in the intake air flow that is provided by air passing over a venturi that is located in the intake air line before that air flow enters the engine, with, for a turbo charged engine, manifold pressure or boost must be present at a predetermined volume in the flow prior to its entering the intake of a turbine compressor.
So arranged, with the presence of LPG in the intake air flow, the burn efficiency of the combustion of fuel in the engine is markedly improved to from ninety three (93) to ninety five (95) percent from a normal burn efficiency of from seventy five (75) to seventy eight (78) percent.
The LPG converter and regulator housing is preferably manufactured from solid aluminum billets by machining methods for arrangement together, providing smooth un-pitted surfaces, including the surfaces of interior passages. The LPG converter and regulator includes a LPG inlet valve that has a valve body and seat and is operated under vacuum, and includes contacting surfaces that are formed at slightly different slope angles at their points of contact, providing an interference fit, to effect a positive and immediate valve closure, limiting leakage, when the LPG flow is cut off. At cut off of LPG flow is provided by an LPG lockoff valve that is opened electrically through a pressure switch on a turbo charged engine, or by a micro switch on a naturally aspirated engine. The flow, as is controlled by the respective pressure or micro switch provides, in a separate line, a vacuum that is created by the passage of the flow across a venturi that moves a diaphragm that is maintained within the converter and regulator housing that flexes and closes off the LPG inlet valve, providing for a rapid line purge.
The LPG cutoff valve is normally open and closes at a manifold at the turbine manifold upon sensing, by individual high and low pressure sensors, pressures of approximately three (3) psi to fifteen (15) psi and may also be opened with a micro switch that is operated upon sensing of engine accelerator peddle travel. In operation, when that manifold pressure falls to below the three (3) psi or upon a sensing of a high pressure of approximately fifteen (15) psi and greater, the LPG cutoff valve is closed. In practice, a line purge occurs in less than one (1) second after an operator removes their foot off of the accelerator, providing a line vacuum that pulls all vaporized LPG from the housing that then travels into the air inlet flow. The rapid and positive LPG flow shut off through the LPG cutoff valve can, accordingly, be controlled by the high and low pressure switches, though, it should be understood, a single pressure switch, or by the use of a micro switch sensing engine acceleration as a function of accelerator peddle depression. Further, LPG outlet and the cutoff diaphragms are provided that are each individually fitted to seal against machined edges of the housing faces, that, when lifted out of engagement with which housing faces edges, provide for rapid LPG purging.